[gnome-session] autostart: validate autostart condition gsettings key

[Ray Strode <halfline src gnome org>]

commit 3442740ad4808f91fb857fb2dda3c24992f0bbdf
Author: Matthias Clasen <mclasen redhat com>
Date:   Fri Nov 14 09:49:21 2014 -0500

    autostart: validate autostart condition gsettings key
    
    gnome-session will crash if fed a desktop file with an
    autostart condition that references an invalid key for
    a given schema.
    
    This commit validates that the key associated with the
    autostart condition is defined in the schema and defined
    to have a boolean type.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=740119

 gnome-session/gsm-autostart-app.c |   23 ++++++++++++++++++++++-
 1 files changed, 22 insertions(+), 1 deletions(-)
---
diff --git a/gnome-session/gsm-autostart-app.c b/gnome-session/gsm-autostart-app.c
index 21a6004..437fb0c 100644
--- a/gnome-session/gsm-autostart-app.c
+++ b/gnome-session/gsm-autostart-app.c
@@ -337,12 +337,16 @@ setup_gsettings_condition_monitor (GsmAutostartApp *app,
         GSettingsSchemaSource *source;
         GSettingsSchema *schema;
         GSettings *settings;
+        GSettingsSchemaKey *schema_key;
+        const GVariantType *key_type;
         char **elems;
         gboolean retval = FALSE;
         char *signal;
 
         retval = FALSE;
 
+        schema = NULL;
+
         elems = g_strsplit (key, " ", 2);
 
         if (elems == NULL)
@@ -358,9 +362,24 @@ setup_gsettings_condition_monitor (GsmAutostartApp *app,
         if (schema == NULL)
                 goto out;
 
+        if (!g_settings_schema_has_key (schema, elems[1]))
+                goto out;
+
+        schema_key = g_settings_schema_get_key (schema, elems[1]);
+
+        g_assert (schema_key != NULL);
+
+        key_type = g_settings_schema_key_get_value_type (schema_key);
+
+        g_settings_schema_key_unref (schema_key);
+
+        g_assert (key_type != NULL);
+
+        if (!g_variant_type_equal (key_type, G_VARIANT_TYPE_BOOLEAN))
+                goto out;
+
         settings = g_settings_new_full (schema, NULL, NULL);
         retval = g_settings_get_boolean (settings, elems[1]);
-        g_settings_schema_unref (schema);
 
         signal = g_strdup_printf ("changed::%s", elems[1]);
         g_signal_connect (G_OBJECT (settings), signal,
@@ -370,6 +389,8 @@ setup_gsettings_condition_monitor (GsmAutostartApp *app,
         app->priv->condition_settings = settings;
 
 out:
+        if (schema)
+                g_settings_schema_unref (schema);
         g_strfreev (elems);
 
         return retval;